[release-6.6]fix(syslog): skip empty KubernetesMinimal prefixes for non-container logs (LOG-9694)

[vparfonov]

Description

Syslog forwarding with KubernetesMinimal enrichment unconditionally added namespace_name=, container_name=, pod_name= prefixes even to audit and journald logs that have no Kubernetes metadata.

Now these fields are only included when present and non-empty.

/cc @Clee2691
/assign @jcantrill

Links

• Depending on PR(s):
• GitHub issue:
• JIRA: https://redhat.atlassian.net/browse/LOG-9694
• Enhancement proposal:

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[qodo-for-rh-openshift]

PR Summary by Qodo

Fix syslog KubernetesMinimal to omit empty k8s prefixes on non-container logs

🐞 Bug fix 🧪 Tests 🕐 20-40 Minutes

AI Description

• Stop prepending empty KubernetesMinimal fields to audit/journald syslog messages.
• Build syslog message prefixes only from present, non-empty Kubernetes metadata.
• Add functional coverage for RFC3164/RFC5424 to prevent regressions.

Diagram

graph TD
  A["Audit / Journald inputs"] --> B["Vector VRL: KubernetesMinimal"] --> C["Syslog sink"] --> D{{"External syslog receiver"}}
  E["App container logs"] --> B

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High-Level Assessment

The following are alternative approaches to this PR:

1. Deduplicate the VRL snippet (single source of truth)

• ➕ Avoids drift between the Go-generated transform and the example TOML
• ➕ Simplifies future enrichment tweaks and reduces copy/paste risk
• ➖ May require generator/template refactoring work beyond the immediate bug fix
• ➖ Could increase coupling between generator code and documentation/examples

2. Always emit keys but omit separators when empty

• ➕ Keeps a more uniform message shape across sources
• ➕ Potentially simpler matching logic for receivers expecting fixed ordering
• ➖ Still risks awkward/ambiguous formatting and parsing issues
• ➖ Does not fully address the visual/semantic noise that prompted the bug report

Recommendation: The PR’s approach (build a prefix list from present + non-empty Kubernetes fields, otherwise forward the original message) is the best behavioral fix and minimizes surprises for non-container logs. Consider a follow-up to deduplicate the VRL logic between the generator and the TOML example to prevent future divergence.

Files changed (4) +158 / -14

Bug fix (2) +42 / -14

syslog.goConditionally build KubernetesMinimal syslog message prefix +21/-7

Conditionally build KubernetesMinimal syslog message prefix

• Reworks the VRL used for KubernetesMinimal enrichment to only prepend namespace/container/pod fields when they exist and are non-empty. If no Kubernetes fields are present, the message is forwarded without any empty prefixes.

internal/generator/vector/output/syslog/syslog.go

tcp_with_kubernetes_minimal_enrichment.tomlUpdate syslog TOML example to skip empty KubernetesMinimal prefixes +21/-7

Update syslog TOML example to skip empty KubernetesMinimal prefixes

• Updates the TOML transform example to mirror the new conditional-prefix behavior. Ensures audit/journald-like records without Kubernetes metadata do not get 'namespace_name=, container_name=, pod_name=' prefixes.

internal/generator/vector/output/syslog/tcp_with_kubernetes_minimal_enrichment.toml

Tests (2) +116 / -0

rfc3164_test.goAdd RFC3164 functional coverage for non-container logs with KubernetesMinimal +58/-0

Add RFC3164 functional coverage for non-container logs with KubernetesMinimal

• Adds functional tests asserting that audit and infrastructure journal logs do not include empty KubernetesMinimal prefixes when forwarded via RFC3164 syslog. Also checks collector logs for absence of VRL compilation warnings.

test/functional/outputs/syslog/rfc3164_test.go

rfc5424_test.goAdd RFC5424 functional coverage for non-container logs with KubernetesMinimal +58/-0

Add RFC5424 functional coverage for non-container logs with KubernetesMinimal

• Adds the same regression coverage as RFC3164, validating that audit and infrastructure journal logs forwarded via RFC5424 do not contain empty Kubernetes prefix fragments and that the collector has no VRL compilation warnings.

test/functional/outputs/syslog/rfc5424_test.go

[jcantrill]

/label release/6.6

[qodo-for-rh-openshift]

Code Review by Qodo

🐞 Bugs (0) 📘 Rule violations (0) 📜 Skill insights (0)

Context used

⚠️ Tickets: not configured — ticket URL found in PR but could not be fetched — check ticket provider credentials

✅ Compliance rules (platform): 9 rules

1. VRL precedence breaks condition ✓ Resolved 🐞 Bug ≡ Correctness

Description

In KubernetesMinimal enrichment, to_string(.kubernetes.*) ?? "" != "" is unparenthesized and can
be parsed as to_string(...) ?? ("" != ""), producing a non-boolean expression in the if and
potentially failing VRL compilation (breaking syslog forwarding when enrichment is enabled). The
same expression is duplicated in the generated example TOML, so both need to be fixed to keep
templates consistent.

Code

internal/generator/vector/output/syslog/syslog.go[167]

+if exists(.kubernetes.namespace_name) && to_string(.kubernetes.namespace_name) ?? "" != "" {

Relevance

⭐⭐⭐ High

Syslog VRL compilation warnings/regressions are routinely fixed; parenthesizing avoids
invalid/non-boolean if expressions.

PR-#3344
PR-#3322

ⓘ Recommendations generated based on similar findings in past PRs

Evidence

The PR introduces unparenthesized ?? combined with != in the new KubernetesMinimal if
conditions. Elsewhere in this repo, when combining a comparison with ??, the expression is
explicitly parenthesized, indicating precedence matters and should be made explicit here too.

internal/generator/vector/output/syslog/syslog.go[159-186]
internal/generator/vector/output/syslog/tcp_with_kubernetes_minimal_enrichment.toml[81-107]
internal/generator/vector/filter/apiaudit/policy.vrl.tmpl[39-46]

Agent prompt

The issue below was found during a code review. Follow the provided context and guidance below and implement a solution

### Issue description
The VRL condition `to_string(.kubernetes.<field>) ?? "" != ""` is ambiguous without parentheses and may be parsed as `to_string(...) ?? ("" != "")`, which can lead to VRL type-check/compilation failure.

### Issue Context
This VRL is used for syslog `KubernetesMinimal` enrichment. The same VRL snippet is duplicated in an example TOML and should remain consistent.

### Fix Focus Areas
- internal/generator/vector/output/syslog/syslog.go[167-176]
- internal/generator/vector/output/syslog/tcp_with_kubernetes_minimal_enrichment.toml[88-97]

### Suggested change
Update each condition to explicitly coalesce first, then compare, e.g.:
```vrl
if exists(.kubernetes.namespace_name) && ((to_string(.kubernetes.namespace_name) ?? "") != "") {
 parts = push(parts, "namespace_name=" + to_string!(.kubernetes.namespace_name))
}
```
Repeat for `container_name` and `pod_name` in both files (or assign the coalesced string to a variable and reuse it).

ⓘ Copy this prompt and use it to remediate the issue with your preferred AI generation tools

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[openshift-ci]

@jcantrill: The label(s) /label release/6.6 cannot be applied. These labels are supported: acknowledge-critical-fixes-only, platform/aws, platform/azure, platform/baremetal, platform/google, platform/libvirt, platform/openstack, ga, tide/merge-method-merge, tide/merge-method-rebase, tide/merge-method-squash, px-approved, docs-approved, qe-approved, ux-approved, no-qe, rebase/manual, cluster-config-api-changed, run-integration-tests, verified, ready-for-human-review, approved, backport-risk-assessed, bugzilla/valid-bug, cherry-pick-approved, jira/skip-dependent-bug-check, jira/valid-bug, ok-to-test, stability-fix-approved, staff-eng-approved. Is this label configured under labels -> additional_labels or labels -> restricted_labels in plugin.yaml?

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[jcantrill]

/approve

[openshift-ci]

[APPROVALNOTIFIER] This PR is APPROVED

This pull-request has been approved by: jcantrill, vparfonov

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[vparfonov]

/label release/6.6

[openshift-ci]

@vparfonov: The label(s) /label release/6.6 cannot be applied. These labels are supported: acknowledge-critical-fixes-only, platform/aws, platform/azure, platform/baremetal, platform/google, platform/libvirt, platform/openstack, ga, tide/merge-method-merge, tide/merge-method-rebase, tide/merge-method-squash, px-approved, docs-approved, qe-approved, ux-approved, no-qe, rebase/manual, cluster-config-api-changed, run-integration-tests, verified, ready-for-human-review, approved, backport-risk-assessed, bugzilla/valid-bug, cherry-pick-approved, jira/skip-dependent-bug-check, jira/valid-bug, ok-to-test, stability-fix-approved, staff-eng-approved. Is this label configured under labels -> additional_labels or labels -> restricted_labels in plugin.yaml?

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/label release/6.6

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[openshift-ci]

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[vparfonov]

/refresh

[jcantrill]

/lgtm